SDCL § 32-26-43: Maximum number of passengers in front--Violation as misdemeanor.

No person may drive a vehicle when it is so loaded, or when there are in the front seat such a number of persons, exceeding three, as to obstruct the view of the driver to the front or sides of the vehicle or as to interfere with the driver's control over the driving mechanism of the vehicle. A violation of this section is a Class 2 misdemeanor.